The present disclosure relates a rotor and a motor.
A rotor used in a motor disclosed in Japanese Laid-Open Utility Model Publication H05-43749 is a rotor having a Lundell-type structure and includes a pair of rotor cores each having a plurality of claw-shaped magnetic poles in a circumferential direction and assembled with each other. By arranging a field magnet as a disc magnet between the rotor cores, the respective claw-shaped magnetic poles are caused to function as alternately different magnetic poles.
A Lundell-type rotor structure has an advantage of being able to easily achieve multipolarity by a simple structure due to the formation of the magnetic poles on the claw-shaped magnetic poles by the disc magnet between the rotor cores.
In the Lundell-type rotor structure, the claw-shaped magnetic poles have a three-dimensional shape radially protruding outward from a core base and axially extending from a radially outer end. Thus, unlike rotors of general technology in which a cross-sectional shape in a direction perpendicular to an axis is the same at all positions, Lundell-type rotors cannot easily adjust an output characteristic and the shape of the claw-shaped magnetic poles is changed for each target characteristic. This leads to a cost increase.
Further, an output characteristic of the Lundell-type rotor structure is affected by main magnetic flux generated from the disc magnet between the rotor cores. Thus, it is desired that the shape of the rotor more be made suitable for achieving a higher motor output.
Further, in the Lundell-type rotor, the number of components tends to be large. Associated with this, there has been a problem that the number of assembling steps increases.